The Adh gene and its ultimate product ADH are being analyzed in an effort to understand the process of gene regulation in Drosophila. This system has several advantages for an analysis of this kind. For example, ADH is present in large amounts in adult Drosophila and is readily purified. The primary structure of the protein is known. Enzyme activity is unessential for survival. Most importantly, chemical selection techniques have been developed that allow the detection and isolation of mutations in Adh, and revertants, recombinants and potential suppressor mutants. Using this system we will carry out the following lines of research: 1. We will follow the synthesis and degradation of ADH in wild-type and mutant stocks. 2. We will isolate and characterize the polysome class that synthesizes ADH. 3. We will isolate the ADH mRNA. 4. We will continue intracistronic mapping of Adh-negative mutants.